Offsetting the needle beds in relation to each other is performed by, for example, a mechanical cam control at the time the carriages are in the reversing position at the ends of the needle beds. Both needle beds are moved towards each other. Offset takes place either by a set amount of the needle gauge of the needle bed in the form of a so-called racking for transfer or by one or more needle gauges in the form of a so-called entire needle offset for the production of particular patterns such as, for example, a braided pattern.
In more recent developments a change has been made from the purely mechanical cam control to an electrical offset control by means of a servomotor, at the same time moving only one of the needle beds. Such a device for the offset control of the needle beds of flat-bed knitting machines is known from German Laid-open Patent applications DE-OS No. 2938 388 and DE-OS No. 30 26 381. In the first of these known devices a zero transducer is used which only emits a signal if the zero offset positions has been attained as the center position. Nothing is directly mentioned in the second known device about a comparison of the set point value with the actual value.
If the flat-bed knitting machine, for whatever reasons, was intentionally or unintentionally turned off during the production of knitted fabric and now must be started again, and if during this period the offset of the respective needle bed either took place or was controlled, the problem arises of knowing where the servomotor or the movable needle bed were at this time. For reasons of a possible break of the fabric just being knitted it is not possible to return the movable needle bed into a zero position and to attain from here the desired set point value. Such a movement of the movable needle bed across several gauges would lead to tearing of the knitted fabric and damage to the needles.